In 2008, about 70,000 new infants were infected with human immunodeficiency virus (HIV) due to transmission of HIV from mother to child through the breast milk. Our goal is to induce HIV-neutralizing antibodies in the saliva to enable neutralization of HIV in the milk and prevent HIV transmission from mother to child. To achieve this goal we will exploit the natural immunocompetence of the oral cavity (OC). The OC is naturally endowed with many lymphoid tissues, such as tonsils, and with dendritic cells (DCs) in the mucosal tissue. DCs are potent antigen presenting cells that can help induce strong mucosal immunity by processing the antigen and presenting it to T-cells resident in the lymphoid tissues. In the OC there is a DC- rich zone, which is located in the upper few hundred micrometers of the OC mucosal epithelia. We will engineer and develop a vaccination approach based on microscopic needles called microneedles (MNs) that can target vaccines in close proximity to the DCs with microprecision. MNs were originally developed for painless vaccination through the skin. We postulate that MNs can be optimized to enable rapid and efficient delivery of vaccines to the oral epithelium and can generate mucosal and systemic responses. We will develop vaccine-coated MNs such that they can deliver their coatings in the DC-rich region of the OC epithelium. The objectives of this application are two fold: (i) to characterize and optimize microneedle coatings to achieve high antigen stability and delivery efficiency and (ii) to compare OC and intramuscular (IM) routes of immunization in rabbits using well characterized HIV antigens with focus on anti-HIV antibodies in the saliva, and at other distal mucosa. We will use serum, saliva, rectal fluids and vaginal fluids to compare systemic and mucosal immune responses through measurement of antigen specific antibodies and neutralizing antibodies against HIV-1. The outcomes expected from this research include a method for efficient and minimally invasive delivery of vaccines to OC epithelium, and an understanding of humoral mucosal immune response locally in the OC, at other distant mucosal surfaces and in the systemic compartment. These results are anticipated to advance the field of OC vaccination by providing fundamental new knowledge of OC immune responses from local HIV vaccine delivery. The new knowledge may also be applicable to other immuno-pathological conditions of the mouth such as oral cancer and gingivitis. PUBLIC HEALTH RELEVANCE: This project seeks to develop a novel methodology to deliver HIV vaccines to the OC and induce neutralizing antibodies in the saliva with the goal of stopping transmission of HIV from mother to child. The delivery methodology will have broad application with respect to other local diseases of the mouth such as periodontal and gum diseases.